I felt like i explained it pretty clearly but It seems you're a special case and your brain has flat out rejected the idea of accepting reality so i'll try to try to break it down to a level that wont be as challenging to process and hopefully will disrupt as little as possible that hard earned ability to accept the utter bullshit that you are fed as truth.
Balance in league is the existence of counter-play or at-least weakness in playing toward and extreme.
The fact that tanks out DPS carry roles when building pure defense has no counterplay. For example you can build a semi tank dps role or a full dps role but after a 50 min game when the full tank top laner is dealing double your damage the game is not balanced and the meta is broken.
Elise isn't as effective of a champion for sven. Elise is a champion that can create really unexpected ganks early and mid game but she pays for that because she has a very punishing or at least useless skill rotation if the cocoon misses, doesn't have an insanely fast clear and isn't an extremely good counter jungler. No where did I say sven played elise badly. It just wasnt as effecitive as his other picks and the early-mid game environment reflected that. I dont know what other champs are in svens pool but sven is a player that goes for way more than locking in a good single target cc combo in a lane, not saying that that is easy to do or isn't valuable in some comps.
If you didnt see how much weaker tsm as a whole was the second game in ganks, map pressure, and just general intensity the second game which had a lot to do with the fact that tsm does well early and mid game a large part because of how proactive and dangerous sven can be in the mid and early game is what makes them lethal. Each lane can and has the ability to create leads in lane which is already huge but its svens ability to outpressure and create advantages in jungle that straight up pushes tsm into the lethal category.